New penny, rinse well with water, and cut apart so students can see abraham lincoln's concave portrait, demonstrating that the image was stamped into the zn core, then plated with cu. Post-1982 pennies are only plated with copper, they are mostly zinc the amount of copper on a post-1982 penny is miniscule and costs more to remove than melt va lue is answered. Next, show a sample calculation for volume of the penny (measuring method), the density of the penny (any method), and the % composition of copper in a penny (pick one) that is a total of three calculations. Ib chemistry experiment 4 composition of a post-1983 penny lab report background: through the use of percent composition one can easily find out how much of a certain element is in a compound or an item such as a post-1983 penny. A post 1981 penny is hollowed out by the protons of hcl that oxidizes the zn but cannot oxidize the cu.
If your penny is dated earlier than 1982, it is copper in 1943, copper was heavily in demand to be used in war materials for world war ii because of this, the 1943 penny was made of steel. Penny post credit union was formed in 1996 as a joint project between royal mail, the communication workers union (cwu), communication and managers' association (cma) and welfare services we are committed to providing an easy and safe way for our members to save and manage money. Before 1982, the lincoln cent was made on a 95% copper planchet due to the cost of materials, a planchet change was needed in the 1980s it was decided that a change to a 992% zinc planchet plated with copper was the economical alternative. First weigh a post 1982 penny measure about 15ml of 10m hno3 and put in medium sized beaker under the fume hood adding the penny to the solution to be dissolved dilute your solution to 250ml in a 250ml volumetric flask.
What you must find out is how much copper and how much zinc it takes to make a penny which has a mass of 2500 grams you can use the mass of the new penny to figure out what the average density of the penny must be, given its mass of 2500 grams you also are given the densities of copper and zinc. In order to determine the amount of copper in a penny various concentrations of copper solutions were made for use as standards in preparation of a calibration curve the concentration of the stock solution used to prepare the standards was 00155 m cu2. 1982 was chosen as the transition year to put this change into effect, and many millions of solid copper and copper-coated zinc cents were produced in 1982 so as to discourage saving or hoarding by the public. We will determine the density twice once for pennies from 1982 or later and once for pennies from prior to 1982 in 1982 the composition of pennies was changed because they contained more than 1 cent's worth of copper.
What measurable property distinguishes a pre-'82 penny from a post-'82 penny in 1982 the composition of the penny was changed from being one of nearly pure copper to that of a zinc center with a copper coating. The experimental density of pre-1982 pennies and post-1982 pennies graph: using the volume of the pennies and the actual mass of the pennies, create a graph of your data. Mole calculations chemical equations and stoichiometry 21 pre-1982 pennies (after 1982 pennies are mostly zinc with copper coating) penny ~ 3g cu 1mol/l.
The rising price of copper has made it so that the metal content of pre-1982 one-cent pieces is now worth more than the one cent the coin represents, falling somewhere around 12 cents. Alternatively, a penny can also be placed in a flask to which conc hcl is added to demonstrate that the reaction is a result of reduction potentials note - it is important to use pennies dated pre-1982 as pennies made in 1983. If your lincoln memorial penny has a date before 1982, it is made of 95% copper if the date is 1983 or later, it is made of 975% zinc and plated with a thin copper coating. Each 25 dollar box of pennies has a typical composition of 80 percent post-1982 pennies and 20 percent pre-1982 copper pennies let's assume each pre-1982 copper penny is worth 2 cents and each post-1982 (and 1982 itself) non-copper penny is worth 1 cent (its face value) 20 percent of 25 dollars is 5 dollars 80 percent of 25 dollars is 20 dollars. As of january 21, 2014, a pre-1982 penny contained 220325 cents' worth of copper and zinc, making it an attractive target for melting by people wanting to sell the metals for profit in comparison, post-1982 copper-plated zinc cents have a metallurgical value of only 055152 cents.
Maybe you've heard that some 1982 lincoln memorial cents are made from brass and worth saving — but you aren't sure how to tell a copper 1982 penny from a zinc 1982 lincoln cent or, perhaps you're trying to find out about the various kinds of 1982 lincoln cents and need some help in finding out what these different 1982 penny varieties. Pennies minted in the united states since 1982 no longer contain pure copper metal this change was due to the fact that the cost of the copper metal required to produce a penny was higher than the face value of the penny. Post-1982 pennies an example of the element zinc: sample image post-1982 pennies before 1982, us pennies were made of solid copper after the price of copper briefly went over a penny per penny, they reconsidered, and now pennies are copper plated zinc. Post-1982 pennies contain a different metal coated with a very thin layer of copper density is an important property of matter by itself, or in conjunction with other properties, density can be used to identify substances.
While some people may think that all pennies are made entirely from copper, virtually every one-cent coin made since late 1982 has a composition consisting of 975% zinc and 25% copper. If your lincoln memorial penny has a date before 1982, it is made of 95% copper if the date is 1983 or later , it is made of 975% zinc and plated with a thin copper coating for pennies dated 1982 , when both copper and zinc cents were made, the safest and best way to determine their composition is to weigh them.
Produce elemental cu from the mass of copper recovered, the percent cu in a pre-1982 penny will be calculated 72 precautionary measures. Lab no_____ - percent composition of a cu penny objective - to determine the percent copper in a post 1982 penny use data collected to perform several stoichiometric calculations. % copper in post-1982 pennies 1 the problem statement, all variables and given/known data the total mass of each penny is 2500g, the density of copper is 896g/ml, the density of zinc is 714g/ml and the mass of a penny if it was 100% copper would be 311g.